The present invention relates to a run-flat device intended to be fitted to a tubeless mounted assembly for a motor vehicle and such a mounted assembly incorporating this device, allowing a significant distance to be covered at a relatively high speed when the mounted assembly is partially or fully deflated.
For a one-piece rim, the known run-flat devices generally consist of a rigid support ring which is mounted tightly around a wheel rim inside a tire cover. This ring is, for example, formed either as a single piece with relatively flexible side walls that may be continuous or alternatively or an open (i.e. split, from which a slice has been removed) flexible piece, or from at least two rigid pieces in the form of arcs of a circle or sectors.
Document WO-A-79/00612 discloses a run-flat device for a one-piece rim with a circumferential rim well, of which the ring is formed of several sectors each produced in two parts which are axially juxtaposed straddling this rim well, and which are hinged together to allow a bead of the tire cover to be brought into the rim well at the time of assembly. Each of these two parts is provided with a reinforced rubber clamping belt which is designed to keep them axially and radially in contact with the rim.
Document EP-A-104 977 discloses a run-flat device for a wheel rim with several blocks accepting a tire cover, which comprises a ring that supports the tire cover under run-flat conditions and an annular clamping belt circumferentially clamping the ring and applied to a circumferential radial indentation of the support face of the ring.
One major disadvantage with the known run-flat devices for one-piece rims lies notably in the rigidity of the ring used, which allows only a relative absorption of shocks under run-flat conditions.
Another disadvantage with these known devices for one-piece rims lies in the need to use as many rings as there are different rim well profiles capable of accommodating them.